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Unformatted text preview: Geol 101 Igneous Rocks continued 02/10/2007 12:45:00 ← Intermediate • Andesite and Diorite ← Mafic • Fe, Mg, Silicates, dark • Oceanic crust, moon, mars, venus • Gabbro and basalt ← Ultra Mafic • Mantle • Olivine ← Bowen’s Reaction Series • Bowen: o Magmatic differentiation by fractional crystallization o Oppose of partial melting – snow cone • Observation – olivine crystallized first o Basalitc magma 50% SiO2 o Olivine 40% SiO2 • Crystallization of olivine will leave the residual liquid a little richer in silica • Discontinuous Reaction Series o (fig 4.17) o Handout is important read it ← Continuous reaction series • Crystal structure remains unchanged • Ionic substitution • Limited by diffusion-slow • Ca2+ and Al3+ out/ Na1+ and Si4+ in • Zoned crystals due to chemical disequilibrium • Zoned crystals will be high in calcium and aluminium in the middle and as you...
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This note was uploaded on 04/28/2008 for the course GEOL 101 taught by Professor Olinsky during the Fall '08 term at Texas A&M.
- Fall '08